Provide SqlAdvisor via JDBC interface

This is work in progress.
Table function itself is implemented, however, `OptiqCatalogReader` turns out to be not ready for `SqlAdvisor`: `getAllSchemaObjectNames` just returns null.

PS. I do not like the way `SqlValidatorImpl#findAllValidUdfNames`: it asks all the object names in schema, then filters via `if (objName.getType() == SqlMonikerType.FUNCTION) {`.